SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb00333c219e243794ba767b24a95286a48312f44d09dd7d4d5d07150eb75396' 
  AND token = 'XKHctABx9yaviF2myWrEjfuQPWaJ8KbrwGuHZVzSjMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}